There are currently two main types of lock architectures in widespread use today. These lock architectures are typically known as the cylindrical lock and the tubular lock designs. Each of these designs has advantages and disadvantages in comparison to the other.
While there are variations, traditionally, a cylindrical lock consists of a chassis, an inside mounting plate, an outside mounting plate and rose, an inside rose, a fixed backset latch, an inside and outside knob/lever, and mounting screws. The fundamental workings of the cylindrical lock provide the conversion of rotational motion of the knob/lever to linear motion—within the chassis housing—to retract the latch. The typical cylindrical lock architecture uses a drawbar occupying the axis of the latch bore. The cylindrical lock architecture typically is more expensive to manufacture, but allows more functional variations than a tubular lock and generally provides better security. The chassis has a fixed spindle-end to spindle-end length which easily accommodates a push-button locking mechanism, however this also results in a varying distance from the end of the knob/lever to the surface of the door when used with different door thicknesses. Installation of a cylindrical lock is generally more complicated than that of a tubular lock. During installation of the cylindrical lock, the inside knob/lever, rose, and mounting plate need to be removed. The chassis needs to be centered in the door by adjusting the outside rose. Additionally, the design constraints inherent in the cylindrical architecture make it impossible to have a dual backset latch which does not require some type of adjustment. Where available, these adjustable backsets used in cylindrical locks are failure-prone and inferior to fixed backset latches.
A tubular lock architecture traditionally consists of an inside chassis complete with a rose and a knob/lever attached, an outside chassis also complete with a rose and a knob/lever attached, a latch, and mounting screws. This simple design allows for easy and quick installation of the tubular lock design with virtually no adjustment required. Due to its simplicity, the tubular architecture also provides a cost advantage over the cylindrical lock. The tubular lock design also provides a fixed distance from the surface of the door to the end of the lever even when used with different door thicknesses. The tubular lock architecture converts rotational motion of the knob/lever to linear motion within the latch in order to retract the latch. Accordingly, a drawbar occupies the axis of the latch bore. However, due to the edge bore of a door preparation, the amount of latch retraction is restricted. In addition, rose locking mechanisms used in a tubular lock utilize a moveable locking mechanism located in the latch to lock the door. Other problems are found in that design constraints make it impossible to design a consistently functioning push button lock because of the chassis datum on the surface of the door. Since the door thickness variation is considerably greater than the push button linear travel, no direct means are available to provide a secure consistent locking action. The tubular lock architecture is also generally less secure than a cylindrical lock architecture.
Accordingly, there remains a need in the art for a lock architecture which combines the advantages of both the tubular lock architecture and the cylindrical lock architecture along with other advantages, while minimizing or removing the limitations existing in each of the prior art designs. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.